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Low Pressure and Rattle at Start up

Posted: Mon Jul 29, 2019 2:09 pm
by docwatson
I've noticed that my oil light stays on for a few seconds after start up and my top end seems to be making a fair amount of noise as well. The oil pressure light may stay on for 2-3 seconds whereas before it seemed like a second or two. Sporadically it will stay on for even longer.

I thought maybe my drainback valve on my oil filter failed so I changed the oil and filter but its still occuring after 1000 miles (WIX w/ Vavoline HW 5w-30).

Oil pressure remains in the middle of the gauge when idling.

Any thoughts? Should I open up my valve covers and look around? What should I even be looking for besides obvious signs of wear?

Posted: Tue Jul 30, 2019 5:44 pm
by docwatson
Strange update. I was doing my rear brakes today and apparently it starts smoother after having the rearend elevated? Could it maybe be a pickup tube problem?

Posted: Wed Jul 31, 2019 6:54 pm
by disallow
oil level ok?

Posted: Thu Aug 01, 2019 3:52 pm
by docwatson
Yeah oil level slightly below the top dot. When I park it facing uphill its slightly worse.

My last oil change I used Mobile 1 0w-40 which may have been too thick for the VQ40 and caused the top end noise.

Or this noise may have been occuring all along but I couldn't hear it over my timing chain whine. Once the motor is warm it quiets down so maybe I am just being sensitive.

Posted: Thu Aug 01, 2019 4:01 pm
by disallow
I run 5 or 0w30. Never an issue.

Why you run 40 weight?

Posted: Thu Aug 01, 2019 4:05 pm
by docwatson
I generally run 5W-30 but read some good used oil analysis results on BITOG of 0W-40 in the VQ40 so I thought I'd give it a shot. Never again.

Posted: Thu Aug 01, 2019 4:56 pm
by smj999smj
There's a chance you could have the dreaded oil gallery cover gasket leak on the rear timing cover letting the oil bleed out of the gallery when it sits.

Posted: Fri Aug 02, 2019 7:51 am
by docwatson
Smj,

That is actually my greatest fear considering I just had it stripped all the way down for the timing chain repair. I really have no desire to do that again.

I'll pull the valve cover this weekend and peek around a bit then monitor from there.

Posted: Fri Aug 02, 2019 11:39 am
by palmerwmd
docwatson wrote:Yeah oil level slightly below the top dot. When I park it facing uphill its slightly worse.

My last oil change I used Mobile 1 0w-40 which may have been too thick for the VQ40 and caused the top end noise.

Or this noise may have been occuring all along but I couldn't hear it over my timing chain whine. Once the motor is warm it quiets down so maybe I am just being sensitive.
The ow-40 is not too thick especially not in summer.
Also Mobil 1s 0w-40 is one of the thinner 40 weights.. on the thin side of the range..
Probably could be written as a 0w-36 if that rating was API alllowed.

Posted: Sun Aug 04, 2019 5:26 pm
by docwatson
Where would the oil galley leak show? Its got to go somewhere right?

Posted: Sun Aug 04, 2019 9:17 pm
by smj999smj
docwatson wrote:Where would the oil galley leak show? Its got to go somewhere right?
The oil would leak past the oil gallery cover gasket and run back to the oil pan. Here's a good article on it with pics:

https://www.motor.com/wp-content/upload ... E_0116.pdf

Posted: Wed Aug 07, 2019 5:45 pm
by docwatson
Thanks smj. I park it facing down hill and there is little to no noise and the pressure builds quickly. If I park it facing up hill pressure takes quite a bit longer and its quite noisy. Really strange to me but I'll just keep parking it facing down hill until some other symptom arises as oil pressure is fine at idle and the noise goes away after about a minute or so.

If it gets weird, I'll report back.

I have noticed exactly the same thing, with some noise.

Posted: Mon Oct 14, 2019 9:42 am
by Brmadsenad
Your description of oil-light seeming to stay on a couple seconds longer than expected is spot-on with my experience.

We had a cold spell here recently, and when very cold I was getting what sounded like valve-tapping coming from engine until it had run for a good while. Once warm, the noise goes away.

I was wondering if it was just an old and worn oil pump?

I'm at 178K miles and haven't done my timing chain ever, so I am thinking sometime in the not too distant future I will be diving into the front cover. If there's a solution for the delayed oil pressure and noise, I'd like to do it all at once. I'll watch this thread!

Posted: Mon Oct 14, 2019 5:55 pm
by smj999smj
A "worn" oil pump would provide low oil pressure all of the time. And while anything can happen, bad oil pumps in Nissans is almost unheard of. There have been a few who have replaced oil pumps on VQ engines due to low oil pressure issues, but most of them didn't fix the issue because the problem the whole time was a leak at the oil gallery cover gasket on the rear timing cover. So, if one is going to tear down the engine to that point to replace the oil pump, it would be prudent to address the cover gasket, as well, because that is more likely the issue and, even if it is the pump, no one wants to do that job twice.

Posted: Fri Oct 18, 2019 7:00 am
by docwatson
I did an oil change with Royal Purple 5w-30 and its running better. I think allowing my timing chain guides to wear for so long may have built up some sludge deposits in smaller passageways.

Or its the rear timing chain cover leak and RP added some new life to the seal and bought me a little more time.

I'll tell you more once I get it back from the transmission shop...